Gearbox noise reduction by electrical drive control

Abstract

A system for damping audible noise from a drive train. One embodiment is a system with an audible noise signal from a drive train wherein a damping circuit produces a damping torque that is a phase shifted and amplified version of the noise signal that is applied to the air-gap torque of a generator or motor coupled to the drive train and effectively reduces the audible noise.

Description

FIELD OF THE INVENTION[0001]The invention relates generally to noise reduction, and more particularly to the reduction of noise in electrical drives.BACKGROUND OF THE INVENTION[0002]There are numerous studies concerning the effects of low frequency noise on humans. While the results are somewhat subjective with respect to the effects of such noise, there is a growing tendency to reduce noise effects from industrial sources wherever possible to maintain goodwill with the end users and the public. The term low frequency as used herein refers to noise in the audible frequency range from about 20 Hz to several hundred Hertz. For reference purposes, the hearing range of most humans is typically about 20 Hz-20 KHz and termed the audible frequency range.[0003]For reference purposes, the article prepared by the Renewable Energy Research Laboratory, Dept. of Mechanical and Industrial Engineering, University of Amherst (June 2002) entitled “Wind Turbine Acoustic Noise” describes the general n...

AI Technical Summary

Benefits of technology

This patent describes a system and method for reducing audible noise in a drive train. The system uses a vibration or noise signal from the drive train to create a damping torque signal. This signal is then applied to an electric machine to reduce the audible noise. The technical effect of this system is a reduction in the amount of audible noise in a drive train, which can provide a quieter and more pleasant experience for users.

Problems solved by technology

The complexity arises when various electrical, electromechanical and mechanical systems are operating in an integrated fashion, such as a wind turbine, where it is difficult to accurately pinpoint the exact source of any audible noise.

The sources of such industrial noise are numerous, however it is generally recognized that one such source of low frequency noise comes from the drive trains from electrical and electromechanical systems.

Various forms of passive and active noise cancellation schemes have been used to lower or eliminate the low frequency noise with some limited success and often by complex designs.

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